Kelly bar coupling

ABSTRACT

A DRIVE ASSEMBLY FOR AN EARTH DRILLING DEVICE WHEREIN THE LOWER DRIVING SHAFT IS COUPLED TO THE UPPER DRIVEN SHAFT BY A COUPLING WHICH IS SLIDABLY RECEIVED AND RETAINED ON THE UPPER DRIVEN SHAFT. THE ASSEMBLY ALSO INCLUDES A LATCH PIN MOUNTED ON THE COUPLING AND ROTATABLE TO A POSITION LATCHING THE COUPLING IN CONNECTED POSITION OR IN A POSITION ABOVE THE LOWER END OF SAID UPPER DRIVEN SHAFT.

United States Patent O M 1m; cl. riad 1/10 U.s. CLM-23.5 s claimsABSTRACT F THE DISCLOSURE fA drive assemblyfor an earth drilling devicewherein the lower driving shaft is coupledto the upper driven shaft-byacoupling which is slidably rreceived and retained-.on the upper drivenshaft. The assembly also in`- cludes a latch pin mounted on the couplingand rotatable to a position latching the coupling in connected positionor in a position above the lower end of said upper driven shaft. Y

BACKGROND OF THE INVENTION Y. Field ofthe invention This inventionrelates to a drive assembly.

I. i Description of the prior art i Certain types of vertical portableearth drills include a driven shaft and a driving shaft between whichysome disalignment is expected 'and allowable. Thus in portable earthdrilling rigs it is cnunon to connect a vertical drive stud from a gearbox mounted on a drill frame, carried by a vehicle, to a vertical Ikellybar, from which a rotary table is driven. The kelly bar is located abovethe gear box and is a part of the Vuprightportion of the drill. Suchdrill rigs incorporate means to fold the upright portion of the drillso-as to'reduce the height of the drill when the lvehicle is moved fromplace to place. Thus lit is desirable that the coupling between thekelly bar and the gear box be such as to keep as smallV as possible theproportion between the part of the drill that does not fold and the partof the drill that does fold. One example of the prior art in this areais disclosed in the patent to Fehrman et al. 3,309,898, n l

SUMMARY OF THE INVENTION One embodiment of this invention might involveYin a drive assembly for use with an earth drilling device including alower shaft, an upper shaft, said upper shaft adapted to be swung awayfrom said lower shaft, and a coupling interconnecting said shafts, saidcoupling including an upper section having a hub portion which has anoncircular hole through it conforming in shape and size to a crosssection of a lower end of said upper shaft and adapted to slidablyreceive said lower end, and a lower section having a hub portion whichhas a noncircular hole through it conforming in shape and size to across section of an upper end of said lower shaft and adapted toslidably receive said upper end, said upper conforming hole beingsmaller in each corresponding cross sectional dimension than said lowerconforming hole, the improvement which comprises abutment means fixed tothe lower end of said upper shaft and extending radially outwardly Y3,553,980 Patented Jan. 12, 1971 ICC Another object of this invention isto provide a reliable coupling which does not have a tendency to becomedisconnected during operation.

Still another object of this invention is to provide an improved drillassembly.

A further object of this invention is to provide a coupling which iscapable of accommodating misalignment.

Still a further object of this invention is to provide a portable earthdrill drive which permits quick and easy connection and disconnection ofa kelly bar and a drive train.

Related objects and advantages will be apparent as the descriptionproceeds.

BRIEF DESCRIPTION OF THE DRAWING y FIG. l is a side elevation partiallyin section of the coupling of the present invention.

FIG. 2 is a top plan view with the kelly bar removed of the coupling ofthe present invention.

FIG. 3 is an enlarged section taken along the line 3-3 of FIG. 2 in thedirection of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularlyto the drawings, there is illustrated a driving shaft 10` which iscoupled to a kelly bar or driven shaft 11 by means of the coupling 12.The driving shaft 10 is cylindrical in outer configuration and is keyedto a generally externally square shaped `member 15 by means of keys 16received within suitable grooves in both the shaft 10 and the externallysquare shaped member 15. The kelly bar 11 is also externally squareshaped but has a smaller externally square shaped size than does theexternally square shaped member 15. For the purposes of thisdescription, the members 10 and 15 are considered to be a compositedriving shaft.

The coupling 12 includes an upper section 17 and a lower section 20. Theupper section 17 has a hub portion 21 which has a square shaped hole 22through it conforming in size and shape to a cross section of the lowerend of the kelly bar 11 and adapted to slidably receive the lower end ofthe kelly bar 11. Fixed to the lower end of the kelly bar 11 by a screw25 is a at round (cylindrical) disc 26 which acts as an abutmentlimiting the downward axial movement of the coupling 12. Thus, thecoupling 12 is shown in its lowenmost position in FIG. l, the couplingbeing movable upwardly on the kelly bar to various other positions abovethe illustrated position.

The lower section Z0 of the coupling also has a hub portion 30 which hasa square shaped hole 31 through it conforming in size and shape to theexternal configuration of member 15. When the member 15 is receivedwithin the hole 31 the coupling is slidable up and down relative to themember 15. In one specific embodiment of the invention, the externalsize of the member 15 is three inches lwhile the internal dimension ofthe hole 31 is between 3.030 and 3.040 inches. Thus, it can beappreciated that a relatively loose connection is provided between themember 15 and the coupling 12.

A latch pin 50 is rotatably mounted within a bore 51 in the hub 21. Thebore 51 intersects the upper hole 22. The latch pin 50 includes a latch52 which is flattened on one side at 55 but which has its fullcylindrical shape at the other sides thereof, such as, for example atthe side 56. Fixed to the latch pin 50 is a lever `60 which permitsrotating of the latch pin to the non-latched position illustrated inFIG. 1 or to a position in which the portion 56 of the latch projectsinto one or the other of a pair of recesses 58 and 59 in the kelly bar.When the latch 52 is projected into the recess 58, the coupling 12 islocked in the position of FIG. 1. When the latch 52 is projected intothe recess 59, the coupling is locked in a position such that the lowerend ofthe coupling is above the plate 26. Each of the recesses 58 and 59has a complementary configuration to the latch cylindrical shape `56.

A screw 61 has received therein a spring 63 which acts against a ball 65retained -within the recess 66 in the screw by means of inturned end`67. The ball 65 acts as a detent by engaging one or the other of a pairof bores 70 and 71 in the latch pin 50. A jam nut 62 is received uponthe screw 61 and is used to lock the screw in any desired positionproviding the proper amount of spring action retaining the latch pin inone or the other of the positions indicated by the reception of the bale65 in either of the bores 70 or 71. In order to maintain smooth actionof the latch pin, a zerk fitting 75 is provided in the end of the latchpin so as to make possible placing grease or other lubricating materialinto the interior of the latch pin for lubricating the bores 70 and 71.A suitable passage 74 leads from the zerk fitting to the bores 70 and71.

The coupling 12 is provided with an external cylindrical outwardlyprojecting flange 100 which may be engaged or grasped by the operator tolift the coupling or to move it between the positions determined by therecesses or grooves 58 and 59 in the kelly bar.

It will be evident from the above description that the present inventionprovides an improved coupling which remains coupled to a portion of thestructure when the coupling is disconnected as well as when the couplingis connected so as to prevent loss of the coupling. It will also beevident that, by the provision of the groove 58 and the latch pin 50,means are provided for retaining the coupling coupled by keeping thecoupling down against the plate 26 so that jiggling or misalignment ofthe coupling does not cause the coupling to disconnect. The different insizes of the hole 31 and the member 15 also permits misalignment of thecoupling and the driving shaft. It can also be appreciated that thepresent invention also permits easy and quick disconnection of thedriving and driven shafts.

The invention claimed is:

1. In a drive assembly for use with an earth drilling device including alower shaft, an upper shaft, said upper shaft adapted to be swung awayfrom said lower shaft, and a coupling interconnecting said shafts, saidcoupling including an upper section having a hub portion which has anoncircular hole through it conforming in shape and size to a crosssection of a lower end of said upper shaft and adapted to slidablyreceive said lower end, and a lower section having a hub portion whichhas a non-circular hole through it conforming in shape and size to across section of an upper end of said lower shaft and adapted toslidably receive said upper end, said upper conforming hole beingsmaller in each corresponding cross sectional dimension than said lowerconforming hole, the improvement which comprises abutment means fixedtothe lower end of said upper shaft and extending radially outwardlybeyond the lower end of said upper shaft, said abutment means beingsized smaller than the lower section hole and received therein to limitthe downward axial movement of said coupling.

2. The drive assembly of claim 1 additionally comprising a latch pinrotatably mounted in said coupling, a latch on said latch pin, saidupper shaft having a first groove therein, said latch pin beingrotatable between two positions in one of which said latch projects intosaid upper hole and is in said groove so that said upper driven shaft islocked against axial movement relative to said coupling and in the otherof which said latch is withdrawn into said coupling and does not projectinto said upper hole so that said coupling is movable axially .relativeto said upper shaft, a lever fixed to said latch pin for rotationthereof, and a ball detent in said coupling, said latch pin having apair of recesses therein one of which is engaged by said ball when saidlatch pin is in one of said positions and the other of which is engagedby said ball when said latch pin is in the other of said positions, andspring means acting between said ball and coupling and yieldablymaintaining said ball in said recesses for yieldably retaining saidlatch pin in said positions.

3. The drive assembly of claim 2 wherein said upper shaft has a secondgroove spaced from and above said first groove and so positioned that,when said latch is in said second groove, said coupling is positionedabove the lower end of said upper shaft.

4. The drive assembly of claim 3 wherein said abutment comprises a atround disc fixed to said upper shaft by a screw coaxial with said -uppershaft.

5. The drive assembly of claim 1 wherein said abutment comprises a flatround disc fixed to said upper shaft by a screw coaxial with said uppershaft.

References Cited UNITED STATES PATENTS 2,695,504 ll/ 1954 Magee 64--232,787,144 4/1957 Chauvel 64-23 2,885,231 5/1959 Smith 6423.5X

JAMES A. WONG, Primary Examiner

